The present disclosure relates generally to diamond-like carbon (DLC) and silicon oxynitride (SiOxNy), and more particularly to a low temperature process for forming optically transparent DLC and SiOxNy thin films on a substrate.
Diamond-like carbon, silicon oxynitride and other high-hardness thin films can be produced using various techniques, including sputtering and filtered cathodic arc deposition. DLC and SiOxNy films, for instance, have been investigated primarily for their tribological properties for use as wear-resistant coatings. Diamond-like carbon and silicon oxynitride are lubricious and hard and can beneficially extend the wear life of a workpiece such as a tool bit.
In the various tribological applications, the optical properties of diamond-like carbon and SiOxNy are not typically paramount. DLC-based supermarket scanners, for example, which are beneficially scratch-resistant, generally have a yellow hue. In other applications, however, such as in wear resistant coatings for lenses and displays, transparency and color can be important properties.
It is believed that the optical transparency of DLC and SiOxNy thin films can be improved in situ, i.e., during formation of the films, by increasing the deposition temperature. On the other hand, thin films formed at lower deposition temperatures typically include defects such as graphitic deposits that adversely affect their clarity.
Thus, as the temperature of the deposition increases, various techniques can be used to produce increasingly water-clear DLC or SiOxNy thin films. However, such high deposition temperatures are generally unsuitable for many temperature-sensitive substrates such as glass substrates.
Based on the foregoing, it would be desirable to form optically-transparent diamond-like carbon and silicon oxynitride thin films using a low temperature process that is compatible with glass and other temperature-sensitive substrates.